The problem is the access syntax (repository notation) for the git repository: git@localhost:gitolite-admin.git

It works with the following repository notation, but i have to enter a the password for the user git: sudo -u gitlab -H git clone git@localhost:/home/git/repositories/gitolite-admin.git /tmp/gitadminab

somehow the rsa-key is not correct setup for localhost and the shortcut to the repository does not work, as I have to specify the full path to the git repository.